BAENIDJE. 8l 



vertebral runs forward and inward to the midline. The table below gives the dimensions of 

 the vertebral scutes. These are narrower than they are in B. arenosa of the same size, and 

 the third is longer than in any of the described species. There are 5 small marginal scutes 



lying in front of the first vertebral. Two of these, quadrilateral 



Vertebral. 



Length Width m ^ orrn > about 26 mm. long and 20 mm. wide, occupy respectively 

 the right and left thirds of the front border of that vertebral. A 

 pentagonal scute 25 mm. from side to side occupies the middle 

 J* third. It measures 15 mm. fore and aft; and its narrowed front 



9 z scarcely reaches the margin of the shell, since two other small 



7 scutes come in front of it, one on each side. No sulcus is seen 



along the midline. 



The lateral marginals of B. entities are higher than they are in 

 either B. arenosa or B. clara. The upper border of the one below the anterior angle of the third 

 costal scute stands about 50 mm. above the lower edge of the shell. In the specimen of B. 

 arenosa, No. 1 115, larger than the shell being described, the corresponding marginal hardly 

 reaches 40 mm. The upper borders of the marginals of B. emilire appear to follow closely 

 the sutures between the peripheral bones and the costal plates. 



There appear to be 13 marginals on each side, including the minute anterior one. 



The epidermal sulci of the carapace are deeply imprest; those of the plastron are rather 

 obscure. The intergulars reach about two-thirds the distance to the humero-gular sulcus. 

 There is a row of 5 inframarginals on each side. As to the other plastral scutes, it is not 

 observed that they are especially different from those of B. arenosa. 



It is possible to trace the sutures between all the bones of the shell, except those surrounding 

 a few of the anterior neurals and some of the posterior peripherals; but even these may be 

 located approximately. 



It will be observed that the nuchal does not have the great antero-posterior extent that it 

 does in the recent Pleurodira. The neurals are in general elongated hexagonal, with the broad 

 end forward. The first and second measure together 83 mm., and the front one is probably 

 a little the shorter. Of their width one can not be certain. The third is 55 mm. long, and 

 apparently 30 mm. wide; the fourth, 43 mm. long, 27 mm. wide; the fifth, 43 mm. long, 31 mm. 

 wide; the sixth, 35 mm. long, 32 mm. wide; the seventh, 30 mm. long, and the same in width; 

 the eighth, 30 mm. long, and 34 mm. wide. Behind the last neural comes the pygal, 30 mm. 

 long and 60 mm. wide. No suprapygal is found between the last neural and the pygal. The 

 eighth costal plate occupies the whole lateral border of the eighth neural and, in addition, 

 the postero-lateral portion of the seventh neural. 



The nuchal bone has a fore-and-aft extent of 37 mm. Its width from side to side is about 

 50 mm. in front and about 85 mm. behind. 



There are almost certainly 12 peripherals on each side. The most anterior sutures are 

 easily distinguish!; but, for various reasons, not the posterior ones. Over the bridges the 

 sutures between the peripherals are continuous with the sutures between the costal bones; 

 posteriorly, there is not this correspondence. The sutures are not traceable, but there is 

 undoubtedly one between each two epidermal sulci. 



On the plastron all the sutures are easily distinguisht. The total length of the plastron is 

 320 mm. The epiplastra meet in the midline by a suture 13 mm. long; the length of each bone 

 is 42 mm. The entoplastron resembles that of B. arenosa, as figured by Leidy (Cont. Ext. 

 Fauna W. Terr., pi. xv, figs. 4, 5). Its length is 40 mm.; its breadth 34 mm. The suture 

 between the hyoplastra is 96 mm. long. The mesoplastra meet in the midline for a space 

 of 33 mm. At their outer ends they are 75 mm. wide. The suture between the hypoplastra 

 is 87 mm. long. The xiphiplastral suture is 50 mm. long, and each, measured at its anterior 

 end, is 50 mm. wide. The anterior and posterior buttresses of the plastron are like those of 

 B. arenosa. 



The intergulars measure on the midline 18 mm.; the gulars, 9 mm.; the humerals, 51 mm.; 

 the pectorals, 84 mm.; the abdominals, 42 mm.; the femorals, 64 mm.; the anals, 54 mm. 

 On the bridge are 5 inframarginals. 



In the middle line above there are some longitudinal ridges and grooves and some irregular 

 elevations, which are rudiments or vestiges of an ornamentation similar to that of B. arenosa. 

 6 



